I see a lot of noise and fireflies with Glass BSDF Shader
Glass is something that causes a lot of noise in a cycles. While the proper solution is lots of samples, there are some options to get quicker acceptable results.

The first option added to 2.79 is Denoising

2.81 adds a new denoise composite node that uses Intels Open Image Denoise. CGCookie has a look and comparison.

There are also third party addons such as D-Noise.